Adding or removing a Site Collection Administrator from all Site Collections

So let’s say you have an environment with a bajillion Site Collections and some new hire comes along and wants to be a Site Collection Administrator to every Site Collection in your farm. And because your boss said so. What would you do?

A. Tell him no way jose!

B. Add him to each Site Collection as a Site Collection Administrator manually a bajillion times. And then file for worker’s comp.

C. Tell him to manually request access to each SharePoint site as he goes along.

D. It’s PowerShell time!

If you picked D, I applaud you. Now here’s a PowerShell script that’ll carry this out for you:

A better way for our needs has been to:
1) Create a AD group like domain\SharePointSiteAdmins,
2) Grant this group Full Control to the entire web application through Central Admin -> Manage web applications -> User Policy.